RM's Descendant Narrative reports are in one of three basic formats: NGSQ (National Genealogical Society Quarterly), NEHGS (New England Genealogical and Historical Register), and "outline". RM actually supports three "outline" formats, but I group them together because the best I can tell they are identical formats and differ only in the numbering system.
I've never been sure if the NGSQ and NEHGS systems specify complete specifications for a report format, or if they just specify numbering schemes. I've searched for years for an authoritative answer to this question. I think the distinction is important because I'm not sure if RM actually has to separate out things like marriage and divorce facts to comply with the NGSQ and NEHGS systems provided in complies with their respective numbering schemes.. In any case, RM's implementation of NGSQ and NEHGS systems creates three groupings of facts - one grouping of facts for the first spouse, one grouping of facts common to the two spouses such as marriage and divorce plus a list of the children, and one grouping of facts for the second spouse. It's the grouping of facts common to the two spouses to which you object. I assume you would still want to see the list of the children.
I'm not entirely happy with RM's implementation of the NGSQ and NEHGS systems because of the way they groups the facts. But I think that all three of RM's implementations of "outline" formats is even worse because it can separate out the children of a family to be dozens or even hundreds of pages apart in a report.
Even though it's not perfect, I do think the trick of sharing marriage and divorce facts helps. Also, I frequently split the marriage fact and sometimes the divorce fact into multiple facts. The basic Marriage fact just has the basic marriage date and place and no note. It is shared with the parties to the marriage. And when I have the data, I have a Marriage Record fact with additional information in the note - usually a full transcription of the courthouse marriage record. The Marriage Record fact is not shared with the principals to the marriage and therefore appears only in the grouping of facts common to the two spouses. That seems to help also.
Finally, I put additional white space between three groupings of facts. That also helps.
It's not perfect, but it's the best I can do right now short of abandoning RM and adopting Microsoft Word as my genealogy software of choice.